Messrs. Allen and Pepys on Respiration. 41 1 
by the press, was of the specific gravity of 1,019 ; this would 
make the specific gravity of the lungs ,997, water being 1,000 ; 
hence it appears, that the substance of the lungs, and the con- 
tents of the blood-vessels together, are so near the specific 
gravity of water, that they may be fairly considered as the 
same. 
Then, as the mass of the lungs was equal to 4 pounds of 
water, though 6 , 2 pounds of water were displaced by them, 
and as a pound of water occupies the space of 28,875 cubic 
inches, we have the following calculation : 
lbs. oz. 
6 2 water displaced by the lungs 
4 1 weight of the lungs 
2 1 , or 59,554 cubic inches of air in the lungs, to which 
must be added 31,580 the volume of the air forced into the 
bladder on opening the thorax. 
SMS 4 
and this gives us 91,134 cubic inches, as the air contained in 
the lungs of this person after death ; and when we reflect 
that the air must have been under compression, when the 
lungs were immersed in water, some force being required to 
keep them down, and also that not less than 7 or 8 cubic inches 
must be contained in fauces, &c., we cannot estimate the whole 
at less than 100 cubic inches. 
It is farther to be noted, that these 100 cubic inches would 
occupy much more space in the temperature of the human 
body, than in the mean temperature in which the examination 
was made ; and this difference would be nearly 8 cubic inches ; 
the air left in the lungs, after complete expiration, would 
